Bradley Holt is a co-director of the Northeast PHP conference and has spoken at SXSW Interactive, OSCCON, and CouchConf. He is also the author of this week's Refcard, which is an update to our existing PHP Refcard and covers some of the new features of PHP 5.4. After some edits and feedback from the development team at Engine Yard, the card's sponsor, this card should serve as a must-have reference for PHP developers.

Bradley took a few minutes to answer some questions about the authorship of the card, which you can read below.

DZone: How would you describe the content of this Refcard in a single sentence?

Bradley Holt: The PHP 5.4 Refcard is a great starting point for learning the basics about the latest version of PHP.DZone: What sort of experience does a developer need with PHP in order to take full advantage of this card?

Bradley Holt: The PHP 5.4 Refcard is for beginner to intermediate PHP developers. It's not for complete beginners as readers will need to have some knowledge of things like basic control structures and data types. More experienced PHP developers should find this Refcard helpful, too. For example, there's a section on security that talks about filtering input, escaping output, and password encryption.

DZone: This Refcard is an update to DZone's existing PHP Refcard. What exciting new features of PHP 5.4 do you cover in this card?

Bradley Holt: New PHP 5.4 features covered in this updated Refcard include PHP's built-in web server, the short array syntax, and function array dereferencing. There are also some features available to PHP 5.3 developers added to this iteration of the Refcard including Pyrus, Composer, and anonymous functions (lambdas and closures).

If I can look forward for a moment, PHP 5.5 looks like it may have some exciting new features as well. One of the more important sections of the PHP 5.4 Refcard is a section on password encryption. PHP 5.5 may include a password hashing API that would make the techniques mentioned in this section easier to implement.

DZone: We worked extensively with you to get this card pared down to the essentials, and lost some content in the process. What would you like to have included in this Refcard that didn't make the cut?

Bradley Holt: There was a lot of content that got cut to fit this down to size. I have to give DZone credit here. I had indicated early on that the security section was a very important one to keep and very little ended up getting cut from that section.

The biggest section to be cut was the one on classes and objects. Some of the object-oriented programming features not included were property/method visibility, class constants, static properties/methods, abstract classes, abstract methods, interfaces, traits (introduced in PHP 5.4), late static binding, type hinting, namespaces, autoloading, exceptions, and the Standard PHP Library (SPL). This section alone probably could have fit in an entire Refcard. Some other content that was cut included more details on data types, how to use database transactions with PDO, details on working with the various string syntaxes, more detail on arrays, more examples of working with functions, how to serve static assets using the built-in web server, and further details on working with dates and times.